Abstract
Principal component analysis was used to estimate the physical fitness age (PFA) of middle-aged and elderly men from eight physical fitness variables. The subjects were 184 Japanese men, aged 20 to 75 years, who were recruited in a series of physical fitness tests including oxygen uptake corresponding to lactate threshold (Vo2@LT) and maximal oxygen uptake (Vo2max) . The subjects were categorized into three groups : those (n=134) considered apparently healthy, those (n=35) employed as a cross-validation sample, and 15 patients with coronary heart disease (CHD) . The equation developed for estimation of PFA in healthy individuals (n=134) was PFA=-15.3 PFS+48.0+Z, PFS=0.021 X1+0.037 X2+0.020 X3+0.024 X4+0.017 X5+0.017 X6+0.008 X7+0.016 X8-4.92, Z =0.12 Age-5.8; where PFS=physical fitness score, X1=Vo2max (ml/kg/min), X2=Vo2@LT (ml/kg/min), X3=grip strength (kg), X4=side step (reps/20s), X5=trunk extension (cm), X6=trunk flexion (cm), X7=foot balance with eyes closed (s), and X8=vertical jump (cm) . Analyses of the data revealed that healthy individuals had PFAs (47.7±17.5yr) similar to their chronological ages (CA: 48.0±15.3yr) . In the cross-validation sample, it was confirmed that no difference existed between PFA (51.5±13.8yr) and CA (52.1±11.8yr) . CHD patients, however, had PFAs approximately 15 years older than their CAs (57.7±11.5vs. 72.2±12.3yr) . Since independent variables of the above equation consisted of various physical fitness elements, we defined the score as an index of “physical fitness age”. The importance and usefulness of PFA were discussed in more detail.
